When they came out with any software, they chose the most confusing name possible. "Windows" was a generic term for any the panes in windowing GUI, until MS appropriated the word. Then came "Word", which sounded like about all the competition out there. Once they had the OS market sewn up, they used that to make their other software work better than anyone elses, with undocumented APIs. Then they offered "bundles" which meant, if you used their OS, which of course every business had to, you couldn't afford to turn down their other offerings. This might sound like fair, tough competition, but the reality was that they used their money and clout to run the competition out of business, then their de facto monopoly to make a fortune.
And tough but fair, often gave way to threats. If a retailer didn't play ball, getting rid of competition, they would pull their joint marketing/advertising deals. If a small business came up with anything interesting, they'd swallow it, or run it out of business by any means necessary. This did more to stifle innovation for about 15 years than anything else.
This is only the beginning of why people don't like MS. If we were to all post here, it would become an encyclopedia.